package design.pattern.singleton.type7;

/**
 * @auther gxnualbert
 * @create 2019-10-11-8:52
 */
public class SingletonTest07 {

    public static void main(String[] args) {
        System.out.println("使用静态内部类完成单例模式");
        Singleton instance = Singleton.getInstance();
        Singleton instance2 = Singleton.getInstance();
        System.out.println(instance == instance2); // true
        System.out.println("instance.hashCode=" + instance.hashCode());
        System.out.println("instance2.hashCode=" + instance2.hashCode());

    }

}

// 静态内部类完成， 推荐使用
class Singleton {
    private static volatile Singleton instance;

    //构造器私有化
    private Singleton() {
    }

    //写一个静态内部类,该类中有一个静态属性 Singleton
    private static class SingletonInstance {
        private static final Singleton INSTANCE = new Singleton();
    }

    //提供一个静态的公有方法，直接返回SingletonInstance.INSTANCE

    public static synchronized Singleton getInstance() {
        return SingletonInstance.INSTANCE;
    }
}